A researcher studies a synapse between neurone P and neurone Q. An electrical impulse in neurone P normally causes neurotransmitter to be released and a new impulse to start in neurone Q.
The researcher blocks the receptor molecules on neurone Q so that the neurotransmitter cannot bind to them. No other part of either neurone is affected. Neurone P is then stimulated.
Which result is expected?
neurotransmitter crosses the gap, but no new electrical impulse starts in neurone Q
blocking the receptors on neurone Q prevents neurotransmitter being released from neurone P
the electrical impulse crosses the gap directly and continues along neurone Q
neurotransmitter released from neurone Q starts a new electrical impulse in neurone P
111 exam-style questions on Edexcel GCSE Biology 2.3 The nervous system and brain, covering 2.3.1 Structures and functions of the brain, 2.3.2 Imaging brain function with scanning, 2.3.3 Limitations in treating nervous system damage, 2.3.4 Neurones and impulse transmission, and 2.3.5 Structure and function of a reflex arc. Each one has a worked solution and a mark scheme showing where the marks go.